Needle bearing medical device with three-position shield

ABSTRACT

Needle-containing medical appliances (e.g., hypodermic syringes, i.v. catheter placement units and phlebotomy apparatus) having tubular shields which are adapted to protect users from injury from contact with the needle are disclosed and claimed. A series of raked teeth on the tubular shield cooperate with raised surfaces on the body of the medical applicance to provide three distinct shield-retaining positions, one of which is adapted to lock the shield around the needle in a substantially non-releasable position.

RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 78,386, filedJuly 27, 1987, U.S. Pat. No. 4,752,290.

BACKGROUND OF THE INVENTION

The present invention provides an improved needle-guard assembly formedical devices which are used, for example, in the administration ofdrugs or for the withdrawal of blood. More particularly, tee inventionrelates to needle-bearing medical appliances, such as hypodermicsyringes, i.v. catheter placement units, phlebotomy (blood-collecting)apparatus and the like, furnished with retractable, tubular shieldsdesigned to protect the needle portion of such devices prior to use, andto be locked around the needle after use in order to prevent injury fromaccidental contact.

Needle-bearing devices which are utilized for the subcutaneous orintramuscular injection of medicaments, or for insertion into a bloodvessel are generally manufactured in disposable form so as to reduce therisk of patient infection. One group which remains at risk in dealingwith such devices are health care professionals and housekeepingpersonnel who must handle these skin-puncturing devices after they havebeen used. Contaminated needles present a substantial health hazard andcan result in transmission of a number of potentially life-threateningdiseases.

That this problem has been recognized in the art is evidenced by thenumber of patents which have issued directed to apparatus for shieldingneedles after use, for example, U.S. Pat. Nos. 3,890,971, 4,139,009,4,507,117 and 4,592,744. Of particular interest to the background of thepresent invention are three United States patents which employretractable, tubular shields adapted to surround the needle portion of adisposable hypodermic syringe after it has been used--U.S. Pat. Nos.4,425,120, 4,573,976 and 4,631,057.

U.S. Pat. No. 4,425,120 (Sampson et al) describes a hypodermic syringehaving a tubular shield which is designed to be locked in either aneedle-shielding position or a retracted position. The shield is held ineither of these two positions by means of upstanding pins on the syringebody which are adapted to cooperate with tracks formed in the shield.Locking is accomplished by rotating the shield so that the pin is heldby an offset at the terminus of the track.

A later Sampson et al patent, U.S. Pat. No. 4,573,976, depicts a syringehaving a tubular shield equipped with an upstanding catch which isdesigned to hold the shield in either a needle-covering or aneedle-exposed position. The device shown in this patent is said to bean improvement over the apparatus shown in the patentees' earlier U.S.Pat. No. 4,425,120 patent in that locking and unlocking can beaccomplished without rotational movement of the shield.

U.S. Pat. No. 4,631,057 illustrates a third injury-preventing adaptationwhich permits movement of a tubular guard on a syringe body betweenneedle-covering and needle-exposing positions. The guard is held ineither of these positions by means of a collar located adjacent thedistal end of the syringe barrel. The collar has circumferentialindentations which are adapted to cooperate with projections on theinterior of the tubular guard. This design permits easy disengagement ofthe guard from the latched position when the guard is in the retracted(needle-exposed) position. However, when the guard is in the extended(needle-covering) position, the shield is held in a substantiallypermanent locked condition. Prior to being used to dispense a liquidmedication, a separate shield is required to cover the needle.

SUMMARY OF THE INVENTION

The present invention provides a needle-bearing medical device having atubular shield which is adapted to be held in three positions: a first,releasable, needle-covering position; a second, releasable,needle-exposing position; and, a third, non-releasable, needle-coveringposition. The apparatus is relatively simple in construction andconventional hypodermic syringes, phlebotomy apparatus, intravenouscatheter placement units or other elongated medical devices havinginternal liquid passageways can be readily modified to incorporate suchthree-position shields.

The first, needle-covering position can be used to protect the needleprior to use with a patient, e.g., during shipment. In this condition,an intermediate ridge or annular retaining ring on the barrel of themedical device cooperates with raked teeth located at one end of theprotective shield, on an interior surface thereof, to hold the shield inposition over the needle. To use the apparatus, a medical provider wouldremove any optional safety cap covering the open end of the shield andslide the shield back, out of engagement with the intermediate ridge,and into engagement with a second ridge or annular retaining ringlocated on the distal end of the medical device away from (distal to)the needle.

The three-position shield of the present invention makes it possible todispense with a separate, needle-covering sheath which is customarilyused with these types of medical appliances. However, if a separateneedle sheath is employed, it can be removed after movement of theshield to the needle-exposing position. The medical device can then beused in the normal manner.

After use with a patient, the needle portion of the medical device willbe contaminated. In order to protect those who subsequently come incontact with the apparatus, the medical device of the present inventionis adapted so that the protective shield can be locked firmly over theneedle portion. This is accomplished by advancing the shield forward, inthe direction of the needle, out of engagement with the distal retainingridge and past the intermediate retaining ridge, into contact with araked tooth or series of raked teeth which are provided on the proximalend of the medical device (adjacent the needle).

The teeth on the body of the medical device are adapted to cooperatewith the series of teeth on the protective shield to lock the shieldfirmly over the needle. The angles of these two sets of teeth are suchthat movement of the shield in the direction of the needle is easilyaccomplished until full engagement has been made (evidenced by aratcheting sound as the teeth engage). The angular orientation of theoutwardly-extending teeth on the body of the medical device causes themto act like a series of bearing surfaces, permitting movement of theraked teeth on the shield over the tooth or teeth on the body when theshield is moved in the direction of the needle. However, movement in theopposite direction (away from the needle) is impeded by theinter-locking of the teeth on the two surfaces. When the two sets ofteeth have engaged with one another, the shield can be withdrawn fromits locked position over the needle only by the application of a strongforce or by the use of a tool. In this condition, the shield isrelatively non-releasable.

In a preferred embodiment, the tubular shield is provided with one ormore cut-outs along the shield periphery. The cut-out allows the shieldto be more easily mounted around the body of the medical device,simplifying construction. Another advantage of the cut-out is that itpermits a greater range of motion for the teeth on the shield. As aresult, the teeth do not have to be cut to close tolerances.

The protective shield is preferably manufactured from a resilient,transparent material. A clear acrylic or polyethylene plastic materialwhich can be formed into the required shape by an injection moldingprocess is especially suitable, although other materials and formingmethods can be employed.

Although the apparatus of the present invention is particularly suitablefor use with disposable syringes, i.v. catheter placement units, bloodcollection apparatus and the like, it can be adapted for use withre-usable, needle-containing medical devices which may have beencontaminated through contact with blood or other fluids. The shieldcut-outs facilitate removal of the tubular protective shield with a tool(either prior or subsequent to sterilization) so that the apparatus canbe re-used, if appropriate.

The invention may best be understood by reference to the followingdescription when considered with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, partly in section, of a phlebotomy tubehaving a tubular protective shield in a first, releasable,needle-covering position.

FIG. 2 is an elevational view, partly in section, showing the phlebotomyapparatus of FIG. 1 having the protective shield in a second,releasable, needle-exposing position with a blood collection tubemounted inside the phlebotomy apparatus.

FIG. 3 is an elevational view, partly in section, showing the phlebotomyapparatus with the protective shield in a third, non-releasable,needle-covering position.

FIG. 4 is an isometric view of the phlebotomy tube of FIGS. 1-3 with theprotective shield in the FIG. 1 position.

FIG. 5 is an isometric view of a shielded intravenous catheter placementunit having the shield in a releasable, needle-covering position.

FIG. 6 is an isometric view of a shielded hypodermic syringe having theshield in a releasable, needle-covering position.

FIG. 7 is an elevational view, partly in section, of a second embodimentof a phlebotomy tube in accordance with the present invention whereinthe tubular protective shield is in a first, releasable, needle-coveringposition.

FIG. 8 is an elevational view of the apparatus of FIG. 7 with theprotective shield in a second, releasable, needle-exposing position.

FIG. 9 is an elevational view, partly in section, showing the phlebotomyapparatus of FIG. 7 with the protective shield in a third,non-releasable, needle-covering position.

FIG. 10 is an isometric view of the phlebotomy tube of FIGS. 7-9 withthe protective shield in the FIG. 7 position.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1-4, a disposable, phlebotomy tube of the type usedfor withdrawing blood samples is indicated generally by the numeral 10.Phlebotomy tube 10 is an elongated structure, manufactured from athermoplastic material by conventional molding processes, having aninternal chamber 11, defined by both a cylindrical wall 13 and a basesection 14 which is located proximately to a hollow needle 12. Needle 12has an exterior terminus or point 25 and an interior terminus 26 whichis located inside chamber 11, opposite point 25. Needle 12 is fixedlyheld in position by an annular, needle-mounting sleeve portion 15 ofchamber base section 14 so that needle 13 lies substantially along themajor axis of the phlebotomy tube.

Phlebotomy tube 10 includes a tubular protective shield 16 having afirst end portion 17 and a second end portion 18. Rows of angular,inwardly-depending raked teeth 22 extend circumferentially around aninterior surface 23 of shield 16, adjacent the second end portion 18thereof. Shield 16 is also formed of a thermoplastic material, and teeth22 are formed therein during the molding process.

Outer surface 19 of cylindrical wall 13 is provided with thermoformeddistal retaining ring 20 and intermediate retaining ring 21 forcooperating with raked teeth 22 to releasably hold protective shield 16in needle-covering or needle-exposing positions, respectively.

FIG. 1 depicts phlebotomy tube 10 in a first, needle-covering positionwith protective shield 16 surrounding needle 12. Inwardly-dependingraked teeth 22 are engaged by intermediate ring 21 to maintain shield 16in the closed position. Ring 21 and teeth 22 can be disengaged by theapplication of either upward or downward pressure to shield 16.

In order to utilize tube 10, the operator must first remove protectivecap 27 which covers the opening of shield end portion 17. Shield 16 maythen be retracted, in the direction of distal retaining ring 20, intothe needle-exposing position of FIG. 2. A flange 34 prevents removal ofshield 16 when it is moved to the retracted position.

FIG. 2 shows tube 10 in the second, needle-exposing position. Rakedteeth 22 cooperate with distal retaining ring 20 to releasably holdshield 16 in place. After removal of an optional protective sheath (notshown) from needle 12, the phlebotomy tube is ready for use. When needlepoint 25 is inserted into a blood vessel, blood will flow through hollowneedle 12 and into a partially evacuated blood collection tube 48 whichis removably mounted inside phlebotomy tube internal chamber 11.

Collection tube 48 has a reasonable elastomeric shield 49 at theproximal end thereof which, in the position shown in FIG. 2, is piercedby needle interior terminus 26. Tube 48 provides both a passageway forthe blood being sampled and as a container for holding the blood pendinganalysis.

After a sufficient quantity of blood has been collected in one or moretubes 48, needle point 25 is removed from the patient's blood vessel.Because needle point 25 may be contaminated with pathogens, tube 10 isadapted to prevent injury to personnel who subsequently come intophysical contact with the apparatus.

Protection is accomplished by moving shield 16 from the needle-exposingposition of FIG. 2 to a third, needle-covering position of FIG. 3. Inthis latter position, shield 16 has been advanced downward, in thedirection of needle 12, so that downwardly-depending raked teeth 22 onshield 16 are advanced past intermediate ring 21 (the FIG. 1 position),and into lockable engagement with a series of outwardly-extending rakedteeth 29 located circumferentially around the distal end section 30 ofcylindrical wall 13. Raked teeth 22 and 29 are disposed at acute,complimentary angles which allows movement of shield 16 from theposition of FIG. 2 to that of FIG. 3, but resists movement of the shieldin the opposite direction. The fact that tube 10 has been used can beascertained both from the position of shield 12 with respect to wall 13and by the fact that the shield cannot be moved to a needle-exposingposition.

FIG. 4 illustrates a key-shaped cut-out 35 formed in the surface ofshield 16, distal to needle 12. Cut-out 35 allows outward expansion ofthe second end portion 18 of shield 16 and thus facilitates mountingshield 16 onto the body of the phlebotomy tube, in that shield endportion 18 can be spread open to fit over teeth 29. Moreover, cut-out 35provides some resiliency to shield 16. This resiliency permitsdownwardly-depending teeth 22 to "ratchet" past upwardly-extending teeth29 when the shield is moved into the needle-covering position of FIG. 3,as cut-out 35 expands to allow this movement. The resiliency also servesto maintain tension between the interface of teeth 22 and teeth 29 whichassists in firmly maintaining shield 16 in the secured position.

In the event that one should wish to re-use phlebotomy tube 10 (e.g.,after a sterilization procedure), cut-out 35 facilitates removal ofshield 16 by means of a tool.

FIGS. 5 and 6 show two other embodiments of the medical device of thepresent invention--intravenous catheter placement unit 50 and hypodermicsyringe 60. Catheter placement unit 50 and syringe 60 have tubularprotective shields 16a, 16b slidably mounted around respective hollowneedles 12a, 12b. As is the case with shield 16, used with phlebotomytube 10, shields 16a and 16b are adapted to be moved from the first,releasable position illustrated in FIGS. 5 and 6 to an intermediate,releasable needle-exposing position (wherein shields 16a, 16b are heldrespectively by distal retaining rings 20a, 20b) and, after use, to athird, locked position.

FIGS. 7-10 show an alternative construction of a disposable phlebotomytube 100 adapted with a protective shield 160. Phlebotomy tube 100 isconstructed generally in the same manner as the apparatus depicted inFIGS. 1-4. The major difference between the apparatus of FIGS. 1-4 andthe apparatus of FIGS. 7-10 is that the cylindrical wall 130 of thelater apparatus is provided with a single, outwardly-extending, rakedtooth 290 rather than a plurality of teeth 29 (compare FIGS. 1 and 7).Tooth 290 is located circumferentially around distal end section 300 ofphlebotomy tube cylindrical wall 130. Outwardly extending raked tooth290 is adapted to cooperate with the downwardly depending teeth 220 onthe surface of a tubular protective shield 160 to lock the shield firmlyin place around the needle after the apparatus has been used (See, FIG.9).

Another difference between the apparatus of FIG. 1 and that of FIG. 7 isthat shield 160 is provided with an inwardly-depending shoulder portion90 which extends radially around a second end portion 180 of shield 160.Shoulder portion 90 serves as a check or stop and prevents shield 160from being inadvertently detached from tube 100 when the shield isadvanced to the final, needle-covering position of FIG. 9.

The final difference between the two embodiments is that shield 160 hasa tear drop-shaped cut-out 350, formed in the surface of the shield of160, distal to needle 120 (FIG. 10). Cut-out 350 facilitates themounting of shield 160 onto the body of the phlebotomy tube in the samemanner as key-shaped cut-out 35 in the apparatus of FIG. 4.

Like the apparatus shown in FIGS. 1-4, protective shield 160 can bemoved to: (i) a releasable, needle-covering position (FIG. 7); (ii) areleasable, needle-exposing position (FIG. 8); and, (iii) anon-releasable, needle-covering position (FIG. 9). Operationally,therefore, the apparatus is identical to that of FIGS. 1-4.

Intravenous catheters, hypodermic syringes, and other elongatedneedle-bearing structures can be similarly modified to utilize a single,outwardly-extending, raised tooth on the tube portion of the apparatus,and a shoulder on the protective shield.

Various modifications, alternative constructions and equivalents may beemployed without departing from the scope of the invention asexemplified in the foregoing description and further defined in thefollowing claims.

What is claimed:
 1. In a medical device comprising an elongatedstructure having proximal and distal end sections and an internal liquidpassageway, a hollow needle having a point and an opposite end axiallymounted at said proximal end section of the elongated structure incommunication with said liquid passageway, and a tubular protectiveshield having first and second end portions, said shield mounted arounda portion of said elongated structure and longitudinally movable from aneedle-covering position, wherein the first end portion of said shouldextends beyond said needle point to a needle-exposing position, theimprovement comprising:a plurality of angular, inwardly-depending rakedteeth circumferentially formed along an inner surface of the second endportion of said tubular protective shield; an angular,outwardly-extending raked tooth around the distal end section of saidelongated structure, the angle of said outwardly-extending tooth beingsubstantially complementary to the angle of the inwardly-depending teethon said protective shield; a distal retaining ring extending annularlyaround the distal end section of said elongated structure forcooperating with said inwardly-depending teeth on said protective shieldto releasably hold said shield in a needle-exposing position; anintermediate retaining ring extending annularly around said elongatedstructure, between said outwardly-extending teeth and said distalretaining ring, for cooperating with said inwardly-depending teeth onsaid protective shield to releasably hold said shield in aneedle-covering position; an inwardly-depending shoulder portionextending radially around said second end portion of said tubularprotective shield; and at least one cut-out in the surface of saidprotective shield for facilitating the mounting of said shield aroundsaid elongated structure.
 2. A medical device according to claim 1wherein said elongated structure comprises a hypodermic syringe.
 3. Amedical device according to claim 1 wherein said elongated structurecomprises phlebotomy apparatus.
 4. A medical device according to claim 1wherein said elongated structure comprises an intravenous catheterplacement unit.
 5. A medical device according to claim 1 wherein saiddevice is disposable.
 6. A medical device according to claim 1 whereinsaid tubular protective shield is transparent.
 7. Apparatus according toclaim 6 wherein said shield comprises a thermoplastic material selectedfrom the group consisting of acrylic plastics and polyethylene plastics.8. A medical device according to claim 1 having a single cut-out,wherein said cut-out is adjacent said second end portion of said tubularshield.
 9. A medical device according to claim 1 having at least twocut-outs in the surface of said protective shield, said cut-outs locatedadjacent said second end portion of said tubular shield.
 10. A medicaldevice according to claim 1 further including:a protective cap removablymounted across an open end portion of said tubular shield.
 11. Apparatusaccording to claim 1 wherein said inwardly-depending raked teeth areintegral with said tubular shield.